http://mmajunkie.comLAS VEGAS – The only thing bigger than Jamie Varner’s nether regions were his fists in his UFC return.

After taking a late-replacement fight against the fast-rising Edson Barboza – a matchup most lightweights would avoid at all costs – the former WEC champion sacked up and pulled off one of the year’s biggest upsets.

The fight was part of UFC 146 at MGM Grand Garden Arena in Las Vegas. It aired on FX following additional prelims on Facebook and prior to the pay-per-view main card.

Varner, an often-beleaguered WEC champion, was one of the few lightweights not folded into the UFC after the closing of the promotion. While his 0-3-1 run certainly didn’t help, reported clashes with WEC management also played a part.

But time apparently heals all wounds, and when Evan Dunham dropped off the card with an injury, Varner was tapped the replacement. However, he entered the fight with Barboza as a significant underdog.

After eating some early leg kicks, Varner caught one aimed for his head and forced the fight to the mat. Once back up, Barboza again attacked the lead leg with low kicks, but an aggressive Varner clipped him with heavy punches.

As the blows began to land more frequently, Barboza eventually staggered against the cage and to the ground. Varner then wrapped up the shocking upset with a quick dose of ground and pound.

The stoppage came at the 3:23 mark of the opening round.

Varner (20-6-1 MMA, 2-1 UFC), who went 3-1 in his post-WEC career and briefly considered retirement, now has won three straight fights. He also picks up his first UFC victory since early 2007.

Barboza (10-1 MMA, 4-1 UFC), fighting for the first time since his highlight-reel spinning-wheel-kick KO of Terry Etim at UFC 142, suffers his first career loss.